Stephen Coffeen smothered his 83-year-old father four years ago in St. Petersburg and was arrested on a murder charge.

And then something unusual happened — even prosecutors agreed he was not guilty by reason of insanity. So instead of going to prison, Coffeen was sent in 2011 to a mental health hospital.

That ended Friday, when a judge ruled that Coffeen can be released and move to his home state of California, where he will continue treatment on an outpatient basis.

"It's absurd," said Thomas Coffeen, who is Stephen's brother and the son of the victim, Robert Coffeen. He didn't even know about Friday's hearing until a Tampa Bay Times reporter called him afterward.

Pinellas-Pasco Circuit Judge Nancy Moate Ley said "this is an unusual case, where Mr. Coffeen otherwise lives a law-abiding life and something obviously horribly snaps." She called the killing a tragedy and said "the system is not excusing that."

She also said it was rare for Pinellas-Pasco State Attorney Bernie McCabe's office to agree a defendant is not guilty by reason of insanity. "We don't jump to this conclusion, certainly not in a charge as serious as murder," Ley said.

In this case, experts from the very beginning — including those hired by prosecutors — concluded Stephen Coffeen was insane at the time he killed his father. So insane, they said, that he did not understand what he was doing at the time, and therefore could not be held legally responsible.

After the State Attorney's Office and defense attorneys agreed in 2011 that Coffeen should not be prosecuted, he was sent to a state mental hospital for more than a year and then sent to an unlocked mental health center in Tarpon Springs.

Another mental health expert hired by prosecutors evaluated Coffeen again, and recently concluded he was well enough to be allowed to move back to his home in Davis, Calif., where he must meet regularly with a psychiatrist, a psychologist and a forensic case manager to continue his outpatient treatment.

Attorney Peter Sartes said he understood when Ley said Coffeen could be sent back to the state hospital if he fails to follow through with treatment.

Ley said when someone is found not guilty by reason of insanity "they by law must be in the least restrictive of all environments that is safe for them and society." She said she was bound to follow that law.

Ley also said, as she has before, that Red Bull energy drink didn't play a role in the case. One expert early in the case testified that Coffeen was suffering from sleep deprivation and had drunk a lot of Red Bull at the time of the killing. The purported "Red Bull defense" got nationwide publicity for a time.

Thomas Coffeen said he wasn't surprised by Ley's decision, but he was disappointed and a bit nervous. If his brother could kill one family member, who knows? He was reassured that his brother was leaving the state.

Robert Coffeen was 83, a retired English professor who had recently taken a fall and was using a walker. Stephen Coffeen had not visited his father in more than a decade but came to see him in 2009.

Coffeen smothered his father with a couch pillow during the visit, and made incoherent statements to police afterward. He said he wanted police to make sure to take his rental car into evidence. He also asked officers to make sure no one touched anything inside his father's house because "it is going to show that he (the father) is the crazy one. It was self-defense. He got suffocated. I did it out of self-defense."

Stephen Coffeen, now 44, appeared in the courtroom wearing slacks and a blazer. He had no comment for reporters as he left the courthouse.

Curtis Krueger can be reached at [email protected] or (727) 893-8232. Twitter: @ckruegertimes.